Answer:

<u>Skills needed: Rhombus Geometry</u>
1) We need to understand a property of rhombi (plural of rhombus) that is important in this problem.
--->
is a diagonal in the rhombus.
--->
is also a diagonal in the rhombus.
- In a rhombus, the diagonals are always perpendicular to each other.
---> Let's make the point of intersection of the diagonals as Point E.

---> This angle is needed to solve the problem for y.
2) Using triangle properties:
---> The sum of interior angles of a triangle equal 180.
- Take
, which has 3 angles:


due to rhombus diagonal property
which is given
(what we are trying to solve for)
Let's plug in!
3) 
y equals 42